1. Field of the Invention
The present invention relates to compositions comprising low-chloride alkylated cyclodextrin compositions, and processes for preparing and using the same.
2. Background of the Invention
Hydrophobic, hydrophilic, polymerized, ionized, non-ionized and many other derivatives of cyclodextrins have been developed, and their use in various industries has been established. Generally, cyclodextrin derivatization proceeds via reactions in which —OH groups at the 2-, 3-, and/or 6-position of the amylose rings of a cyclodextrin are replaced with substituent groups. Substituents include neutral, anionic and/or cationic functional groups.
Known cyclodextrin derivatives such as alkylated cyclodextrins include, but are not limited to, sulfoalkyl ether cyclodextrins, alkyl ether cyclodextrins (e.g., methyl, ethyl and propyl ether cyclodextrins), hydroxyalkyl cyclodextrins, thioalkyl ether cyclodextrins, carboxylated cyclodextrins (e.g., succinyl-β-cyclodextrin, and the like), sulfated cyclodextrins, and the like. Alkylated cyclodextrins having more than one type of functional group are also known, such as sulfoalkyl ether-alkyl ether-cyclodextrins (see, e.g., WO 2005/042584 and US 2009/0012042, each of which is hereby incorporated by reference in its entirety). In particular, alkylated cyclodextrins having 2-hydroxypropyl groups and/or sulfoalkyl ether groups have found use in pharmaceutical formulations.
A sulfobutyl ether derivative of β-cyclodextrin (“SBE-β-CD”) has been commercialized by CyDex Pharmaceuticals, Inc. as CAPTISOL® and ADVASEP®. The anionic sulfobutyl ether substituent improves the aqueous solubility and safety of the parent β-cyclodextrin, which can reversibly form complexes with active pharmaceutical agents, thereby increasing the solubility of active pharmaceutical agents and, in some cases, increase the stability of active pharmaceutical agents in aqueous solution. CAPTISOL® has a chemical structure according to Formula X:
                where R is (—H)21-n or ((—CH2)4—SO3−Na+)n, and n is 6 to 7.1.        
Sulfoalkyl ether derivatized cyclodextrins (such as CAPTISOL®) are prepared using batch methods as described in, e.g., U.S. Pat. Nos. 5,134,127, 5,376,645 and 6,153,746, each of which is hereby incorporated by reference in its entirety.
Sulfoalkyl ether cyclodextrins and other derivatized cyclodextrins can also be prepared according to the methods described in the following patents and published patent applications: U.S. Pat. No. 3,426,011, U.S. Pat. No. 3,453,257, U.S. Pat. No. 3,453,259, U.S. Pat. No. 3,459,731, U.S. Pat. No. 4,638,058, U.S. Pat. No. 4,727,06, U.S. Pat. No. 5,019,562, U.S. Pat. No. 5,173,481, U.S. Pat. No. 5,183,809, U.S. Pat. No. 5,241,059, U.S. Pat. No. 5,536,826, U.S. Pat. No. 5,594,125, U.S. Pat. No. 5,658,894, U.S. Pat. No. 5,710,268, U.S. Pat. No. 5,756,484, U.S. Pat. No. 5,760,015, U.S. Pat. No. 5,846,954, U.S. Pat. No. 6,407,079, U.S. Pat. No. 7,625,878, U.S. Pat. No. 7,629,331, U.S. Pat. No. 7,635,773, US2009/0012042, JP 05001102, and WO 01/40316, as well as in the following non-patent publications: Lammers et al., Recl. Tray. Chim. Pays-Bas 91:733 (1972); Staerke 23:167 (1971), Adam et al., J. Med. Chem. 45:1806 (2002), Qu et al., J. Inclusion Phenom. Macrocyclic Chem. 43:213 (2002), Tarver et al., Bioorg. Med. Chem. 10:1819 (2002), Fromming et al., Cyclodextrins in Pharmacy (Kluwer Academic Publishing, Dordrecht, 1994), Modified Cyclodextrins: Scaffolds and Templates for Supramolecular Chemistry (C. J. Easton et al. eds., Imperial College Press, London, UK, 1999), New Trends in Cyclodextrins and Derivatives (Dominique Duchene ed., Editions de Sante, Paris, FR, 1991), Comprehensive Supramolecular Chemistry 3 (Elsevier Science Inc., Tarrytown, N.Y.), the entire disclosures of which are hereby incorporated by reference.
Impurities present in an alkylated cyclodextrin composition can reduce the shelf-life and potency of an active agent composition. Impurities can be removed from an alkylated cyclodextrin composition by exposure to (e.g., mixing with) activated carbon. The treatment of cyclodextrin-containing aqueous solutions and suspensions with activated carbon is known. See, e.g., U.S. Pat. Nos. 4,738,923, 5,393,880, and 5,569,756. However, there is a continued need for alkylated cyclodextrin compositions with higher purity.